Control of the flow of one or more liquids is desirable in many applications. For example, without limitation, where liquids are to be mixed in particular proportions, or where particular amounts of liquids are desired, it is often desirable to control the flow rates to ensure the proper mixture or amount. Typically, as part of this control, a sensor is used to measure flow rate, and a control device, such as a valve, is adjusted in response to the sensed flow rate to achieve the desired flow rate.
A particular application where flow control is desirable is in the dispensing of post-mix beverages. In post-mix beverage systems, beverage syrups and/or flavors are mixed with carbonated or plain water to form finished beverages. In such systems, drink quality is significantly affected by the accuracy of the mixture ratio of these liquids. However, due to variations in the systems, such as, without limitation, pressure changes, temperature changes, drift, and wear issues, flow rates in such systems are not constant. Therefore, it is desirable to control the rate of flow of one or more of the liquids to insure proper mixture ratios.
While systems have been employed to control flows, there is an ever present need to improve their cost, efficiency, and accuracy.